Quantification of Lactose in Lactose-Free and Low-Lactose Milk and Milk Products by BIOMILK 300/3000 Lac, Collaborative Study: Final Action 2020.09

Background: In April 2020, the BIOMILK 300 LAC method for the quantification of lactose in lactose-free and low-lactose dairy products was adopted as First Action Official Method of Analysis(SM)2020.09 by AOAC INTERNATIONAL. To test the reproducibility of the method, as the last step toward the Final Action status, a collaborative study was organized by BIOLAN Microbiosensores. Objective: Fifteen collaborators within the European Union took part in this study, where nine different samples were sent as duplicate blind test portions for lactose determination. The data obtained were used to determine method repeatability and reproducibility and also to validate the new version of the biosensor. Method: The test method is based on the direct enzymatic recognition-electrochemical detection of trace levels of lactose over a wide range of dairy samples by means of the BIOMILK 300 biosensor, in less than 5 min, and without intricate sample pretreatments. Results: All samples resulted in a repeatability relative standard deviation (RSDr) of <8.1% and a reproducibility relative standard deviation (RSDR) of 14% maximum, meeting requirements from Standard Method Performance Requirement (SMPR(R)) 2018.09. Conclusions: The method has proved to give reproducible results for the quantification of lactose in lactose-free and low-lactose dairy products.